Liu Fan, KC Pawan, Zhang Ge, Zhe Jiang
Department of Mechanical Engineering, University of Akron , Akron, Ohio 44325, United States.
Department of Biomedical Engineering, University of Akron , Akron, Ohio 44325, United States.
Anal Chem. 2016 Jan 5;88(1):711-7. doi: 10.1021/acs.analchem.5b02716. Epub 2015 Dec 18.
We present a novel cell detection device based on a magnetic bead cell assay and microfluidic Coulter counting technology. The device cannot only accurately measure cells size distribution and concentration but also detect specific target cells. The device consists of two identical micro Coulter counters separated by a fluid chamber where an external magnetic field is applied. Antibody-functionalized magnetic beads were bound to specific antigens expressed on the target cells. A high-gradient magnetic field was applied to the chamber closer to the second counter via an external cylindrical magnet. Because of the magnetic interaction between the magnetic beads and the magnetic field, target cells were retarded by the magnetic field; transit time of a target cell (bound with magnetic beads) passing through the second counter was longer than that through the first counter. In comparison, transit times of a nontarget cell remained nearly the same when it passed through both counters. Thus, from the transit time delay we can identify target cells and quantify their concentration in a cell suspension. The transit time and the size of each cell were accurately measured in terms of the width and amplitude of the resistive pulses generated from the two Coulter counters. Experiments demonstrated that for mixed cells with various target cell ratios, the transit time delay increased approximately linearly with the increasing target cell ratio. The limit of detection (LOD) of the assay was estimated to be 5.6% in terms of target cell ratio. Cell viability tests further demonstrated that most cells were viable after the detection. With the simple device configuration and easy sample preparation, this rapid and reliable method is expected to accurately detect target cells and could be applied to facilitate stem cell isolation and characterization.
我们展示了一种基于磁珠细胞分析和微流控库尔特计数技术的新型细胞检测装置。该装置不仅能准确测量细胞大小分布和浓度，还能检测特定靶细胞。该装置由两个相同的微库尔特计数器组成，中间隔着一个施加外部磁场的流体腔室。抗体功能化的磁珠与靶细胞上表达的特定抗原结合。通过外部圆柱形磁体向靠近第二个计数器的腔室施加高梯度磁场。由于磁珠与磁场之间的磁相互作用，靶细胞被磁场阻滞；与磁珠结合的靶细胞通过第二个计数器的传输时间比通过第一个计数器的传输时间长。相比之下，非靶细胞通过两个计数器时的传输时间几乎保持不变。因此，通过传输时间延迟，我们可以识别靶细胞并量化其在细胞悬液中的浓度。根据两个库尔特计数器产生的电阻脉冲的宽度和幅度，准确测量每个细胞的传输时间和大小。实验表明，对于具有不同靶细胞比例的混合细胞，传输时间延迟随靶细胞比例的增加近似线性增加。该检测方法的检测限（LOD）估计在靶细胞比例方面为5.6%。细胞活力测试进一步表明，大多数细胞在检测后仍具有活力。凭借简单的装置配置和简便的样品制备，这种快速可靠的方法有望准确检测靶细胞，并可应用于促进干细胞的分离和表征。
